In recent years, the semiconductor industry has experienced rapid growth due to continuous improvement in integration density of various electronic components, e.g., transistors, diodes, resistors, capacitors, etc. Such improvement in integration density is mostly attributed to successive reductions in minimum feature sizes, which allows more components to be integrated into a given area.
In general, the semiconductor device includes various transistors with various threshold voltages to meet customers' need. A native transistor is a kind of the MOS field-effect transistors that are intermediate between enhancement and depletion modes. That is to say, the native transistor is a transistor with nearly zero or negative threshold voltage, while the native transistor has better electron mobility. Therefore, the native transistor is useful for low-voltage, analog, and mixed signal applications. However, there are quite a few challenges to be handled for the native transistor, such as leakage issue, threshold voltage not-matching target issue, etc.